Announcement

Collapse
No announcement yet.

Reel to reel tube recorder Geloso G258, problem

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Reel to reel tube recorder Geloso G258, problem

    Hello my friends.
    I have bought recently a almost unused reel to reel tube recorder, Geloso G258 feom 1958
    But because of his age it is time for changing his electrolytic capacitors.
    I leave in Cyprus so it will be more easy for me to buy them on line because here i don't have many choices in electronic components.

    The capacitors i need are the following.

    *16μf 200ν-250v
    *32μf 350v-500v
    *25μf 30v
    *150MF 15v
    *0,0047μf 20%
    *0,0022μf 25%

    and one double/dual capacitor 25+25μf 200vcc-350v (if i write it correctly)

    Please if you can help me will be a huge help.
    Thanks in advance

    Sorry for my bad English
    Attached Files

    #2
    Re: Reel to reel tube recorder Geloso G258, problem

    Axial electrolytic capacitors are hard to find. I don't know what parts are available in Cyprus.
    I use radial capacitors and bend one lead over. A little bit of silicone caulk/glue to hold it down. Modern capacitors are so much smaller.

    16μF 200V (250V surge) - use 16μF 250V
    32μF 350V (500V surge) - use 33μF 450V (two needed)
    25μF+25μF 200V dual (350V surge) - use two 22uF 250V

    25μF 30V - use 33μF 50V
    150μF 15V - use 220uF 16V or 25V.

    0,0047μF ?V 20% - use 4n7 400V mylar film cap like Epcos B32529C6472
    0,0022μF 630V 25% - use 2n2 400V mylar film cap like Epcos B32529C6222


    Geloso G258 Schematic: https://www.eserviceinfo.com/downloa...loso_G258.html
    Attached Files

    Comment


      #3
      Re: Reel to reel tube recorder Geloso G258, problem

      Really thanks Redwire.
      I will try to find them here but really is difficult in Cyprus.
      There is not any on line way to buy them ?

      Comment


        #4
        Re: Reel to reel tube recorder Geloso G258, problem

        The only 16μF 250V capacitors i can find are for starting motor use with no polarity .
        Can i use no polarity capacitors ?

        Comment


          #5
          Re: Reel to reel tube recorder Geloso G258, problem

          I have ordered them, so just waiting to arrive
          Thanks Redwire. Your help was really big.

          One more question. I must change and this one.
          Any idea with what type and what uf ?
          Electrolytic one ? Bipolar or not ?
          Attached Files

          Comment


            #6
            Re: Reel to reel tube recorder Geloso G258, problem

            You are over 5,000 miles around 9,300km away. I don't know electronics parts distributors over there. RS Components might be good but they like to sell bags of 5 or box of 1000.

            The 0.1uF 400V cap connects to mains, so I would use a film cap 275VAC 0.1uF with X-cap safety rating. Look at Epcos B32653, Kemet R46 series.

            Comment


              #7
              Re: Reel to reel tube recorder Geloso G258, problem

              Originally posted by redwire View Post
              You are over 5,000 miles around 9,300km away. I don't know electronics parts distributors over there. RS Components might be good but they like to sell bags of 5 or box of 1000.

              The 0.1uF 400V cap connects to mains, so I would use a film cap 275VAC 0.1uF with X-cap safety rating. Look at Epcos B32653, Kemet R46 series.
              You are my Hero

              Comment


                #8
                Re: Reel to reel tube recorder Geloso G258, problem

                https://www.badcaps.net/forum/attach...3&d=1571582161
                That is a snubber cap for the switch (it is connected in parallel with the AC switch contacts).
                Never stop learning
                Basic LCD TV and Monitor troubleshooting guides.
                http://www.badcaps.net/forum/showthr...956#post305956

                Voltage Regulator (LDO) testing:
                http://www.badcaps.net/forum/showthr...999#post300999

                Inverter testing using old CFL:
                http://www.badcaps.net/forum/showthr...er+testing+cfl

                Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                http://s807.photobucket.com/user/budm/library/

                TV Factory reset codes listing:
                http://www.badcaps.net/forum/showthread.php?t=24809

                Comment


                  #9
                  Re: Reel to reel tube recorder Geloso G258, problem

                  Originally posted by budm View Post
                  https://www.badcaps.net/forum/attach...3&d=1571582161
                  That is a snubber cap for the switch (it is connected in parallel with the AC switch contacts).
                  Is a important capacitor for the system ?
                  It must be changed or does not really matters ?
                  It is a papper capacitor so for sure does not work correctly any more.

                  Comment


                    #10
                    Re: Reel to reel tube recorder Geloso G258, problem

                    It helps to reduce switch arcing, you should replace it since it is old paper based cap.
                    Never stop learning
                    Basic LCD TV and Monitor troubleshooting guides.
                    http://www.badcaps.net/forum/showthr...956#post305956

                    Voltage Regulator (LDO) testing:
                    http://www.badcaps.net/forum/showthr...999#post300999

                    Inverter testing using old CFL:
                    http://www.badcaps.net/forum/showthr...er+testing+cfl

                    Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                    http://s807.photobucket.com/user/budm/library/

                    TV Factory reset codes listing:
                    http://www.badcaps.net/forum/showthread.php?t=24809

                    Comment


                      #11
                      Re: Reel to reel tube recorder Geloso G258, problem

                      Thanks Budm.
                      I have ordered them and i wait to receive them so i can start the replacing process.
                      It will take some time to receive them but i will update the forum with the process

                      Comment


                        #12
                        Re: Reel to reel tube recorder Geloso G258, problem

                        Hello again guys.
                        I have changed the electrolitic and papper capacitors and the problem is resolved. The recording and erase process now works normally.

                        But i have noticed that when i power on the system, the middle lamp 12AX7 , lights really much for 1/2 seconds , then decrease and remain in the normal light as the other lamps .


                        I believe it is over voltage in first 2 seconds because of some capacitor.
                        Any idea ?

                        This happens only when the system is off for at least 10 minutes.

                        This does not not happen to the other 12AX7 , 6AQ5 or to EM84 lamp.
                        Attached Files
                        Last edited by Lef de art; 11-01-2019, 07:07 AM.

                        Comment


                          #13
                          Re: Reel to reel tube recorder Geloso G258, problem

                          This is normal - when the tube is cold, high current surge for the heater and the fine wires will light up bright orange until the heater is warmed up.
                          Geloso put two 3.3R resistors for tube V1a heater but not the second 12AX7 for some reason. It might be for lower noise and hiss.

                          Comment


                            #14
                            Re: Reel to reel tube recorder Geloso G258, problem

                            Thanks Redwire .
                            It is the lamp. I have changed the position with the other 12AX7 and the phenomenon occurred in the same lamp but this time in the different positions.
                            As i understood is not something important. Does not mean the bulb is defective so everything is ok

                            Comment


                              #15
                              Re: Reel to reel tube recorder Geloso G258, problem

                              Comparing the sound i have now with the sound i had before changing the capacitors i have the filing that i have lost enough bass, low frequencys.
                              As it is normal in the replacement capacitors process it wasn't easy to find the exactly value in capacitors. So some changes was made...
                              There is any chance the following replacements to be wrong?
                              What is your opinion?

                              0,005uf / 150v replaced with 0.0056 250v

                              0,002uf / 400v replaced with 0,0033 400v

                              0,025uf / 300v replaced with 0,027/ 400v

                              0,5uf / 150v replaced with 0,56/ 250v


                              Or this differences are not important?
                              Thanks in advance guys

                              Comment


                                #16
                                Re: Reel to reel tube recorder Geloso G258, problem

                                If the coupling cap between audio stages has decreased value then you will lose low end frequency, but you put in higher value so it should not decrease the low frequency response. The Cathode bypass caps will also affect the low frequency response.
                                https://www.v-cap.com/coupling-capacitor-calculator.php
                                Last edited by budm; 11-06-2019, 04:48 PM.
                                Never stop learning
                                Basic LCD TV and Monitor troubleshooting guides.
                                http://www.badcaps.net/forum/showthr...956#post305956

                                Voltage Regulator (LDO) testing:
                                http://www.badcaps.net/forum/showthr...999#post300999

                                Inverter testing using old CFL:
                                http://www.badcaps.net/forum/showthr...er+testing+cfl

                                Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                                http://s807.photobucket.com/user/budm/library/

                                TV Factory reset codes listing:
                                http://www.badcaps.net/forum/showthread.php?t=24809

                                Comment


                                  #17
                                  Re: Reel to reel tube recorder Geloso G258, problem

                                  I would say those differences do not matter, the capacitors are tiny bit bigger and would not make the bass go weak.
                                  You must have mixed up a capacitor, or a new one is no good, or polarity backwards (for 25uF), or there is a wiring mistake putting in the new capacitor.

                                  Check the capacitors, I think important (for bass) are:
                                  25uF 30V cathode pin 2 EL95 electrolytic
                                  20K 150V grid pin 7 12AX7 V1a
                                  25K 350V plate pin 6 12AX7 V1a
                                  10K 400V plate pin 1 12AX7 V1a / pin 2 12AX7

                                  Comment


                                    #18
                                    Re: Reel to reel tube recorder Geloso G258, problem

                                    Thanks Redwire. I will check them today.
                                    The electrolitic capacitors work all good because i have changed them all in first stage and i then the recording quality was ok.

                                    After i change all the papper capacitors the recording high frequencies are very weak.
                                    And the recording sound has more treble.

                                    But the changes are in recording .
                                    Last edited by Lef de art; 11-07-2019, 04:53 AM.

                                    Comment


                                      #19
                                      Re: Reel to reel tube recorder Geloso G258, problem

                                      The difference is on recording high frequencies .
                                      The recording has lost high frequencies.

                                      The playback mode with old capacitors recordings sounds ok.
                                      Last edited by Lef de art; 11-07-2019, 04:54 AM.

                                      Comment


                                        #20
                                        Re: Reel to reel tube recorder Geloso G258, problem

                                        Did you check/adjust recording bias? Tape heads are cleaned and de-magnetized?
                                        Never stop learning
                                        Basic LCD TV and Monitor troubleshooting guides.
                                        http://www.badcaps.net/forum/showthr...956#post305956

                                        Voltage Regulator (LDO) testing:
                                        http://www.badcaps.net/forum/showthr...999#post300999

                                        Inverter testing using old CFL:
                                        http://www.badcaps.net/forum/showthr...er+testing+cfl

                                        Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                                        http://s807.photobucket.com/user/budm/library/

                                        TV Factory reset codes listing:
                                        http://www.badcaps.net/forum/showthread.php?t=24809

                                        Comment

                                        Working...
                                        X